In a wireless cellular communication system, a user equipment (User Equipment, UE) in the active (Active) state determines a serving cell according to signal power of a cell, while a UE in the idle (Idle) state determines a camping cell according to the signal power of the cell. Therefore, the UE needs to measure signals of the serving cell or the camping cell and signals of neighboring cells.
In a single carrier cell system, one cell has one carrier, and the UE only needs to measure signals on a sole carrier in the serving cell or the camping cell.
With the development of communications technologies, the concept of an aggregated carrier is proposed in a long term evolution advanced (Long Term Evolution advanced, LTE-Advanced) system, that is, multiple carriers are aggregated into a cell and the cell is called aggregated carrier cell and provides the UE with a higher speed of service data. A base station may, according to the capability of the UE and a service type, dynamically schedule each component carrier (Component Carrier, CC), and increase or reduce the number of component carriers used by the UE.
For the aggregated carrier cell, a cell has more than one carrier, and each carrier cannot be measured by using the method in the prior art for measuring a single carrier cell. Therefore, how to measure component carriers in the aggregated carrier cell is an urgent problem to be solved.